Transition radiation (Ginzburg-Frank): ⟨E⟩ ∝ γ · ω_p·(Z_p·ω)/(3c); Lorentz-factor ID

When a charged particle crosses a boundary between media of different dielectric constant, transition radiation is emitted (Ginzburg-Frank 1945). The integrated radiated energy per boundary ⟨E_TR⟩ = α z² γ ℏω_p/3 is linear in Lorentz…